Response to Targeted Therapy Increased From 2006 to 2020 in Patients With Cancer

April 23, 2021
Dylann Cohn-Emery

The eligibility for and responses to genome-targeted oncology agents increased in United States among patients with cancer from 2006 to 2020, according to updated estimates published in the Annals of Oncology.

The investigators estimated that there was a 4.31% increase in response to genome-targeted therapy, from 2.73% in 2006 to 7.04% in 2020. In the United States, the percentage of patients with cancer who responded to this type of therapy was modest. Most of the increase in response was observed prior to 2018 and most of the increase in eligibility was observed after 2018.

“Prior studies have evaluated the percentage of patients [in the United States] with advanced or metastatic cancer who are eligible for and respond to this class of medications,” the investigators wrote in their article. “Specifically, genome-targeted therapy was found to apply to 8.3% of patients as of 2018, and 4.9% might experience a partial or complete response. However, since that publication, the number of FDA approvals for drugs targeting genetic indications has grown rapidly. We, therefore, sought to update the estimates of both eligibility for and response to genome-targeted and informed therapies for drugs that have been FDA-approved to reflect estimates as of 2020.”

To calculate the estimates for genome-targeted therapies, the investigators looked at drugs approved for use based on genomic test results where the detected aberration is targeted by the drug. They also looked at and genome-informed therapies, defined as any drug given after a genomic test regardless of if that drug was meant to target the abnormalities the patient expressed on the test or not.

The FDA-approved genome-targeted or genome-informed therapies were evaluated by the date they were approved, their indication, tumor type, genomic indication, and response rate. By using mortality data from the American Cancer Society, the investigators estimated the eligibility for these drugs based on prevalence statistics. Eligibility was then multiplied by the response rate in the FDA label to create an estimate for the percentage of patients with cancer in the United States who responded.

Spanning 18 cancer types and 36 genomic indications were 72 different approvals for 51 genome-targeted or genome-informed treatments from 2006 to 2020. The eligibility for genome-targeted therapy was estimated to be 5.13% (95% CI, 5.07%-5.19%) in 2006. By the end of 2018, this increased to 8.82% (95% CI, 8.75%-8.90%). In 2020, it was 13.60% (95% CI, 13.51%-13.68%).

In 2006, there was an estimated eligibility for genome-informed therapy of 10.70% (95% CI, 10.62%-10.78%), which in increased to 16.54% (95% CI, 16.45%-16.63%) in 2018, and then 27.30% (95% CI, 27.19%-27.41%) in 2020.

Response to genome-targeted therapy in 2006 was estimated at 2.73% (95% CI, 2.69%-2.78%). In 2018, it increased to 5.48% (95% CI, 5.43%-5.54%) and then 7.04% (95% CI, 6.98%-7.10%) in 2020. Genome-informed therapy responses were estimated at 3.33% (95% CI, 3.29%-3.38%), 7.68% (95% CI, 7.62%-7.75%), and 11.10% (95% CI, 11.03%-11/19%) in 2006, 2018, and 2020, respectively. All of the response estimations were based on the prevalence of the disease and prevalence of the mutation for the respective cancer type.

In the FDA approval notifications for genome-targeted therapy, the median duration of response was 18.9 months (range, 5.7-80 months) in 2006 and 17.6 months (range, 4.6-80 months) in 2020. There was a median response rate of 19.0% (range, 10.6%-95.3%) and 63.5% (range, 12%-95.3%) in 2006 and 2020, respectively.

“With an increasing number of people who are both eligible for and respond to genomic therapies, it is important to consider access to genomic testing,” the investigators wrote in their discussion. “…In considering which genetic markers should be tested, we need to consider those for which there are available treatment options that have been shown to improve meaningful outcomes such as overall survival and not just those mutations that have tests available for them.”

References:

Haslam A. Kim MS, Prasad V. Updated estimates of eligibility for and response to genome-targeted oncology drugs among US cancer patients, 2006-2020. Ann Oncol. Published April 12, 2021. Accessed April 22, 2021. doi:10.1016/j.annonc.2021.04.003